android getWriteableDatabase() 数据库报nullException。很可能是传入的context 为空。

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public class CommentListAdapter extends QBaseAdapter {int size = 0;List<CommentInfo> comlist = null;boolean isShopContext ;private String shopid;public CommentListAdapter(Activity activity,String shopid,boolean isShopContext) {super(activity,shopid);// TODO Auto-generated constructor stubthis.isShopContext = isShopContext;this.shopid = shopid;if(mData==null){mData = new ArrayList<Map<String,Object>>();}System.out.println("comlist mData:"+mData);System.out.println("comlist CommentListAdapter:"+comlist);    //知道这一句会输出啥么？null}@Overridepublic List<Map<String, Object>> getData(Activity activity,String shopid) {// TODO Auto-generated method stub//DBOutHelper out = new DBOutHelper(activity);//comlist = out.readCommentInfo(activity, shopid);System.out.println("comlist:"+comlist);Map<String, Object> map;if (comlist == null)comlist = new ArrayList<CommentInfo>()List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();this.mData = list;return mData;}}

public abstract class QBaseAdapter extends BaseAdapter{protected List<Map<String, Object>> mData;protected LayoutInflater mInflater;protected Activity activity;public QBaseAdapter(Activity activity,String shopid){this.mInflater =LayoutInflater.from(activity);this.mData =getData(activity,shopid);this.activity =activity;}public  abstract List<Map<String, Object>> getData(Activity activity,String shopid);}

分析一下运行流程一下子就知道了。父类调用getData() -> comlist =null(定义） ->子类构造函数